太阳能半导体温差发电器的输出功率

建立太阳能半导体温差发电系统的一般模型 ,应用非平衡态热力学和有限时间热力学理论研究存在四种主要不可逆因素影响的太阳能驱动的半导体温差发电器的性能特性 ,导出发电器的输出功率一般表示式 ,探讨最大输出功率及其有关的优化条件 ,确定了温差发电器输出电流和功率的上限 ,得到一些有意义的新结论 .

太阳能光热光伏或可同步发电

光热和光伏是当今太阳能发展的两条平行线,但是美国科学家的最新科研成果似乎正在让这两条平行线相交。据美国《大众科学》报道,斯坦福大学的工程师们日前找到了一种同时利用太阳的光和热来产生电能的方法,这将能使太阳能产品的效率达到现有方式的3倍,并有可能使太阳能便宜到可以和石油竞争。这种颠覆性的太阳能利用方法被称为"

Construction of a broadband impedance spectrum and synchronous DC voltammetry measurement system for solar cells

The current impedance spectroscopy measurement techniques face difficulties in diagnosing solar cell faults due to issues such as cost,complexity,and accuracy.Therefore,a novel system was developed for precise broadband impedance spectrum measurement of solar cells,which was composed of an oscilloscope,a signal generator,and a sampling resistor.The results demonstrate concurrent accurate measurement of the impedance spectrum(50 Hz-0.1 MHz)and direct current voltametric characteristics.Comparative analysis with Keithley 2450 data yields a global relative error of approximately 6.70%,affirming the accuracy.Among excitation signals(sine,square,triangle,pulse waves),sine wave input yields the most accurate data,with a root mean square error of approximately 13.3016 and a global relative error of approximately 4.25%compared to theoretical data.Elevating reference resistance expands the half circle in the impedance spectrum.Proximity of reference resistance to that of the solar cell enhances the accuracy by mitigating line resistance influence.Measurement error is lower in high-frequency regions due to a higher signal-to-noise ratio.

空气源热泵换热器与岗亭壁体一体化供暖性能

设计一种由太阳能供电、空气源热泵换热器与亭壁一体化的供暖岗亭.首先,建立一体化岗亭设备模型,并采用Matlab语言编制仿真程序,对岗亭进行性能模拟;然后,选取太原某日工况,对岗亭模型进行实验验证,并对其供暖季性能进行分析.结果表明:亭壁蒸发器吸收室内外两侧空气热量、得热量比相同条件下,常规风冷蒸发器高31.41%;供暖季系统性能系数(COP)为3.22~4.96,平均COP值为4.18,高于常规风冷热泵,节能效果良好;供暖季太阳能发电量可满足岗亭热泵压缩机耗电量需求,证明岗亭可实现供暖零能耗.

非均匀热通量对热电器件性能的影响

提高冷热两端温度是提高热电器件发电效率的有效途径之一。但当施加于热端表面的热通量不均匀时,热端表面温度不均匀,系统性能受到影响。基于此,建立了热电器件的热电转换耦合数学模型,分析热电材料物性参数,非均匀热通量等参数对热电器件的功率输出特性的影响。数值模拟结果表明:材料物性参数随温度的变化对系统输出功率的影响不可忽略,热通量4 W·cm-2时物性参数对系统最高温度的影响接近4%;非均匀热通量对热电器件输出特性影响也十分显著,热通量均匀度越小,热端表面温度分布不均匀性越大,极值温度越高,高温区越小,断路电压越低。

POWER GENERATION POTENTIAL OF BIPV APPLICATION IN CHINA

This paper discusses the potential and prospect of building-integrated photovoltaics (BIPV) for solar electrical power generation in China.The BIPV technology has been identified as the most economical renewable energy resource to contribute to world electrical energy demand for protecting environment from reduced fossil fuel consumption.The available solar energy resource of 14 cities and the potential power generation from PV claddings in buildings in China were estimated.The economical analysis of BIPV application is discussed.It is found that the potential is significant and the government should play an important role in its development.

“电网与清洁能源”征稿启事(中国科技核心期刊)

《电网与清洁能源》(原《陕西水力发电》→《西北水力发电》→《电网与水力发电进展》,1985年创刊,2010年入选"中国科技核心期刊"),是经国家新闻出版总署批准,西北电网有限公司主管,西北电网有限公司、西安理工大学水电土木建筑研究设计院主办,国内外公开发行的科技期刊。国际标准出版物号ISSN 1674-3814,国内统一连续出版物号CN 61-1474/TK,月刊。邮发代号52-171。

代表呼吁《上网电价法》出台 光伏产业影响深远

2009年以来,国内大批光伏企业经历了多晶硅价格高位"跳水",行业亦被质疑出现重复建设倾向。我国太阳能生产企业虽然只能触摸国际市场脉博律动,消化大国一打喷嚏,生产企业就感冒。由于是买方市场,生产大国却左右不了市场形势。

China's INDC and non-fossil energy development

Global climate change promotes the energy system reform. Achieving a high proportion of renewable energy becomes the major countries＇ energy strategy. As proposed in its Intended Nationally Determined Contributions （INDC）, China intends to raise the proportion of non-fossil energy in primary energy consumption to about 20% by 2030. That ambitious goal means the non-fossil energy supplies by 2030 will be 7-8 times that of 2005, and the annual increase rate is more than 8% within the 25 years. Besides, the capacity of wind power, solar power, hy- dropower and nuclear power reaches 400 GW, 350 GW, 450 GW, and 150 GW respectively, and China＇s non-fossil power capacity is even greater than the U.S.＇s total power capacity. In addition, the scale of natural gas increases. Consequently, by 2030, the proportion of coal falls from the current 70% to below 50%, and the CO2 intensity of energy consumption decreases by 20% compared with the level of 2005, which play important roles in significantly reducing the CO2 intensity of GDE Since China has confirmed to achieve the CO2 emissions peak around 2030, at that time, the newly added energy demand will be satisfied by non-fossil energy, and the consumption of fossil fuel will stop growing. By 2030, non-fossil energy accounts for 20%, and the large scale and sound momentum of new and renewable energy industry will support the growth of total energy demand, which plays a key role in CO2 emissions peaking and beginning to decline, and lays the foundation for establishing a new energy system dominated by new and renewable energy in the second half of the 21 st century as well as finally achieving the CO2 zero-emission.

Optimization of solar thermal power station LCOE based on NSGA-Ⅱ algorithm

In view of the high cost of solar thermal power generation in China,it is difficult to realize large-scale production in engineering and industrialization.Non-dominated sorting genetic algorithm II(NSGA-II)is applied to optimize the levelling cost of energy(LCOE)of the solar thermal power generation system in this paper.Firstly,the capacity and generation cost of the solar thermal power generation system are modeled according to the data of several sets of solar thermal power stations which have been put into production abroad.Secondly,the NSGA-II genetic algorithm and particle swarm algorithm are applied to the optimization of the solar thermal power station LCOE respectively.Finally,for the linear Fresnel solar thermal power system,the simulation experiments are conducted to analyze the effects of different solar energy generation capacities,different heat transfer mediums and loan interest rates on the generation price.The results show that due to the existence of scale effect,the greater the capacity of the power station,the lower the cost of leveling and electricity,and the influence of the types of heat storage medium and the loan on the cost of leveling electricity are relatively high.

Ⅰ-Ⅲ-Ⅵ chalcogenide semiconductor nanocrystals:Synthesis,properties,and applications

Colloidal semiconductor nanocrystals have been proven to be promising candidates for applications in low‐cost and high‐performance photovoltaics,bioimaging,and photocatalysis due to their novel size‐and shape‐dependent properties.Among the colloidal systems,I‐III‐VI semiconductor nanocrystals(NCs)have drawn much attention in the past few decades.Compared to binary NCs,ternary I‐III‐VI NCs not only exhibit low toxicity,but also a high performance similar to that of binary NCs.In this review,we mainly focus on the synthesis,properties,and applications of I‐III‐VI NCs.We summarize the major synthesis methods,analyze their photophysical and electronic properties,and highlight some of the latest applications of I‐III‐VI NCs in solar cells,light‐emitting diodes,bioimaging,and photocatalysis.Finally,based on the information reviewed,we highlight the existing problems and challenges.

Could It Happen： Global Warming Leads to the Extinction of Mankind？

The upcoming COP23 at Bonn of the UN and its UNFCCC must outline how its COP21 objectives are to be promoted by means of concrete international and national management. Only a massive replacement of fossil fuels and wood coal by solar power parks, can wind power and atomic power save mankind from the grave threats of global warming. This paper presents a tentative estimation of what is involved with regard to the fulfilment of COP21 ＇s GOAL II--decarbonisation to 30-40 per cent of 2005 level of emissions.

A Novel Solar Driven Micro-CliP System： A State of the Art Review

The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat and power （CHP） systems driven by concentrating solar absorbers and supplemented by biomass boilers are proving to be the most promising methods of domestic power generation, μCHP systems eliminate losses associated with power distribution and transmission opposed to the large scale power generation methods. The systems can utilize about 75% of solar energy to provide electric and thermal energy direct to end users. The driving potential behind μCHP systems is the thermal efficiency the systems can achieve and their market significance. Despite huge potential market for μCHP systems, the systems are yet to be seen available in commercial market. Hence the authors of this paper are currently developing such type of CHP system with electricity production being of prime importance.

Absorptive Capacities for Sustainability Technologies:Perspectives from the BRICS and China

For the development process in the rapidly growing economies, knowledge transfer and technology cooperation are becoming important issues. Research and technological competences are key indicators for the absorptive capacity of sustainability technologies and for the ability to export them. These issues are analyzed empirically for Brazil, Russia, India, China and South Africa (BRICS). Sustainability related research in BRICS is mostly carried out within broader, more sector oriented programmes. Specialization patterns of international patents and in foreign trade indicate various strengths and weaknesses of the BRICS countries. The differences within the countries imply that the analysis must proceed at a technology specific level. China has considerable capabilities in technologies such as photovoltaics, solar thermal or buildings. There is a strong need for strategic positioning of the countries and for coordination of the various policy fields involved.

Long-lived Single Excitons, Trions, and Biexcitons in CdSe/CdTe Type-II Colloidal Quantum Wells

Light-harvesters with long-lived excited states are desired for efficient solar energy conversion systems. Many solar-to-fuel conversion reactions, such as H2 evolution and CO2 reduction, require multiple sequential electron transfer processes, which leads to a complicated situation that excited states involves not only excitons （electron-hole pairs） but also multi-excitons and charged excitons. While long-lived excitons can be obtained in various systems （e.g., semiconductor nanocrystals）, multi-excitons and charged excitons are typically shorted-lived due to nonradiative Auger recombination pathways whereby the recombination energy of an exciton is quickly transferred to the third carrier on a few to hundreds of picoseconds timescale. In this work, we report a study of excitons, trions （an exciton plus an additional charge）, and biexcitons in CdSe/CdTe colloidal quantum wells or nanoplatelets. The type- II band alignment effectively separates electrons and holes in space, leading to a single exciton lifetime of 340 ns which is -2 order of magnitudes longer than that in plane CdSe nanoplatelets. More importantly, the electron-hole separation also dramatically slows down Auger decay, giving rise to a trion lifetime of 70 ns and a biexciton lifetime of 11 ns, among the longest values ever reported for colloidal nanocrystals. The long-lived exciton, trion, and biexciton states, combined with the intrinsically strong light-absorption capability of two-dimensional systems, enable the CdSe/CdTe type-II nanoplatelets as promising light harvesters for efficient solar-to-fuel conversion reactions.

Life Cycle Assessment of Enriched Methane Produced by a Concentrated Solar Power Plant Coupled with a Steam Reforming Process

The global energy related challenges, mainly due to the worldwide growing energy consumption gone with a reduction ofoil and gas availability, is leading to an increasing interest on hydrogen as energy carrier. Molten salts at temperatures up to 550 ~C can be used as solar heat carrier and storage system, and hydrogen selective membranes can be used to drive reforming reaction at lower temperatures than conventional （〈 550 ~C）, with hydrogen purification achieved thereby. The combination of new technologies such as membranes and membrane reactors, concentrating solar power （CSP） systems and molten salt heat carriers, allows a partial decarbonation of the fossil fuel together with the possibility to carry solar energy in the current natural gas grid. The aim of this work is to present a life cycle assessment of a novel hybrid plant for the production of a mixture of methane and hydrogen, called enriched methane, from a steam reforming reactor whose heat duty is supplied by a molten salt stream heated up by an innovative concentrating solar power （CSP） plant developed by ENEA. The performance of this plant will be evaluated from an environmental point of view by the use of an LCA software （SimaPro7） and compared with the ones of traditional plants （reformer and cracker for the hydrogen production） for the production of enriched methane.

Evaluating Economic and Environmental Benefits of Integrating Solar Photovoltaics within Future Residential Buildings in Saudi Arabia

Renewable energy options, including solar power, are becoming increasingly viable alternatives to conventional sources of energy, such as oil, coal and natural gas. Solar Photovoltaic （PV） technology is one type of solar energy technologies that has recently received substantial attention because it offers the possibility of providing clean power sources for buildings. The aim of this paper is to examine the economic viability of using solar PV within future residential buildings in the oil-rich Saudi Arabia. Strictly speaking, the prospects of using the PV in order to provide 10% of the electricity to be consumed in the houses, which are going to be built in Sandi Arabia over the period 2010-2025, are examined. The study reveals that significant economic and environmental benefits could be realized as a result of such an endeavor.

Linear Generator Used in Hybrid System Solar Biomass

The aim of this paper is to present the linear generator （Stirling solar dish） in the context of a HSSB （hybrid system solar biomass）, project P ＆ D （research and development P ＆ D 0041, in cooperation and partnership with CPFL--LIght and Force Paulista Company-Campinas, Piratininga, S.P. Brazil）. The other components of the system will be the solar ORC （organic Rankine cycle）, the rotary Stifling and the biomass gasifier. The integration of the complete system will be described in the paper, and is projected to be hydraulic one.